Add SameVersionStartupCounts suffix to startup HardFault and Temperature histograms.

components/startup_metric_utils/browser/startup_metric_utils.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_UTILS_H_
 #define COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_UTILS_H_
 
 #include <stdint.h>
 #include <string>
 
@@ skipping 16 matching lines @@
 enum StartupTemperature {
   // The startup was a cold start: nearly all of the binaries and resources were
   // brought into memory using hard faults.
   COLD_STARTUP_TEMPERATURE = 0,
   // The startup was a warm start: the binaries and resources were mostly
   // already resident in memory and effectively no hard faults were observed.
   WARM_STARTUP_TEMPERATURE = 1,
   // The startup type couldn't quite be classified as warm or cold, but rather
   // was somewhere in between.
   LUKEWARM_STARTUP_TEMPERATURE = 2,
-  // This must be after all meaningful values.
-  STARTUP_TEMPERATURE_COUNT,
+  // This must be after all meaningful values and be equal to the last one.
+  STARTUP_TEMPERATURE_MAX = LUKEWARM_STARTUP_TEMPERATURE,
   // Startup temperature wasn't yet determined.
   UNDETERMINED_STARTUP_TEMPERATURE

[msw, 2016/01/26 18:08:30]

nit: trailing comma

[gab, 2016/01/26 18:15:07]

This is on purpose, this one should always be last, new ones should go above
STARTUP_TEMPERATURE_MAX. I can add a comment if you don't think this is clear.

[msw, 2016/01/26 18:16:51]

Acknowledged.

 };
 
 #if defined(OS_WIN)
 // Gets the hard fault count of the current process through |hard_fault_count|.
 // Returns true on success.
 bool GetHardFaultCountForCurrentProcess(uint32_t* hard_fault_count);
 #endif  // defined(OS_WIN)
 
 // Registers startup related prefs in |registry|.
 void RegisterPrefs(PrefRegistrySimple* registry);
@@ skipping 18 matching lines @@
 // On Android, the entry point time is the time at which the Java code starts.
 // In Mojo, the entry point time is the time at which the shell starts.
 void RecordMainEntryPointTime(const base::Time& time);
 
 // Call this with the time when the executable is loaded and main() is entered.
 // Can be different from |RecordMainEntryPointTime| when the startup process is
 // contained in a separate dll, such as with chrome.exe / chrome.dll on Windows.
 void RecordExeMainEntryPointTime(const base::Time& time);
 
 // Call this with the time recorded just before the message loop is started.
-// |is_first_run| - is the current launch part of a first run.
+// |is_first_run| - is the current launch part of a first run. |pref_service| is
+// an optional parameter which, if provided, will be used to store state for
+// stats that span multiple startups; in its absence those stats will not be

[msw, 2016/01/26 18:08:30]

nit: maybe describe which stats, like the removed function comments?

[gab, 2016/01/26 18:15:07]

This is constantly subject to change so I intentionally left it vague as I think
it's wrong for the API to constantly be updated when metrics are added/removed.
All the caller needs to know is that : if you don't provide this param you're
missing out on all stats that span multiple startups but still getting the stats
specific to the current startup.

[msw, 2016/01/26 18:16:51]

Acknowledged.

+// recorded.
 void RecordBrowserMainMessageLoopStart(const base::TimeTicks& ticks,
-                                       bool is_first_run);
-
-// Logs the Startup.TimeSinceLastStartup histogram. Obtains the timestamp of the
-// last startup from |pref_service| and overwrites it with the timestamp of the
-// current startup. If the startup temperature has been set by
-// RecordBrowserMainMessageLoopStart, the time since last startup is also logged
-// to an histogram suffixed with the startup temperature.
-void RecordTimeSinceLastStartup(PrefService* pref_service);
-
-// Logs the Startup.SameVersionStartupCount histogram. Relies on |pref_service|
-// to know information about the previous startups and store information for
-// future ones.
-void RecordStartupCount(PrefService* pref_service);
+                                       bool is_first_run,
+                                       PrefService* pref_service);
 
 // Call this with the time when the first browser window became visible.
 void RecordBrowserWindowDisplay(const base::TimeTicks& ticks);
 
 // Call this with the time delta that the browser spent opening its tabs.
 void RecordBrowserOpenTabsDelta(const base::TimeDelta& delta);
 
 // Call this with a renderer main entry time. The value provided for the first
 // call to this function is used to compute
 // Startup.LoadTime.BrowserMainToRendererMain. Further calls to this
@@ skipping 22 matching lines @@
 base::TimeTicks MainEntryPointTicks();
 
 // Returns the startup type. This is only currently supported on the Windows
 // platform and will simply return UNCERTAIN_STARTUP_TYPE on other platforms.
 // This is only valid after a call to RecordBrowserMainMessageLoopStart().
 StartupTemperature GetStartupTemperature();
 
 }  // namespace startup_metric_utils
 
 #endif  // COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_UTILS_H_